Hillary needs to make sure her "injury" heals so she can continue getting ready for 2012.
Hillary stands little chance of taking the WH in 2012, if that's her ultimate aim. Obama and the young, hip, liberals have already moved on to a new "young blood" era.
Besides, once 2012 rolls around, Hillary will be even more of a relic of the distant past for Democrats. Her last best shot was 2008, I'm afraid.